Digital image sensors have gained significant popularity in recent years. For example, many digital cameras, mobile computers, and mobile phones include digital image sensors for capturing images.
However, traditional digital image sensors, such as complementary metal-oxide-semiconductor (CMOS) sensors, utilize photodiodes and suffer from dark current associated with photodiodes. The dark current contributes to increased shot noise, which is undesirable.
Although a charge modulation device (CMD) has been proposed as a solution to the dark current problem, charge modulation devices suffer from a small change in on/off signals. In addition, charge modulation devices are limited with a trade-off of a quantum efficiency and a weak channel modulation.